Objective. To evaluate indoor air pollution in hospitality venues in Argentina. Material and Methods. PM2.5 levels were measured in a convenience sample of venues in 15 cities with different legislative contexts following a protocol developed by Roswell Park Cancer Institute. Results. 554 samples were collected. Across all 5 smokefree cities the mean PM2.5 level was lower during daytime vs. evening hours, 24 vs. 98 PM2.5 respectively (p=.012). In the three cities evaluated before and after legislation, PM2.5 levels decreased dramatically (p<0.001 each). Overall, PM2.5 levels were 5 times higher in cities with no legislation vs. smokefree cities (p<0.001). In cities with designated smoking areas, PM2.5 levels were not statistically different between smoking and non-smoking areas (p=0.272). Non-smoking areas had significantly higher PM2.5 levels compared to 100% smokefree venues in the same city (twofold higher) (p=0.017). Conclusions. Most of the participating cities in this study had significantly lower PM2.5 levels after the implementation of 100% smokefree legislation. Hence, it represents a useful tool to promote 100% smokefree policies in Argentina.